I am interested in modifying the exhaust system/muffler for my Honda Civic LX, to raise horsepower and give it that signature sound. My problem is, I want the ignition and acceleration loud but I don't want it to be noisy when coasting down the freeway or doing a steady 65mph. I'm afraid that I'll get it and love it, but get annoyed when driving for long periods of time at a steady speed. Will it annoy me? I would appreciate it if you could link me to some sites with information on exhaust systems and explain to me how a modified muffler works.

I understand ya there, it definately is annoying going down highways at 65 mph with my Ranger, and a kid that had a CRX down in Kansas had a loud ass one, I dont know if they make special mufflers that work that way or not, I wouldn't think so though. I know there are such things as exhaust cutouts, which is basically a Y pipe, but it keeps going to the pipe, but the other section that splits it has a cap on the end that u can screw on and off, but I dont think you'd want that, those are actually made to be welded right into the headers.

You won't notice any realistic increase in speed. Just leave it the way it is for all our sakes.

my buddy had a vw golf with fart can exhaust, once your at a constant speed it isnt loud *with th emuffler he had go figure, it was loud when accel though

*Usually*, in my experience, a glasspack type muffler remains fairly quiet while cruising and idling, compared to a chambered muffler. Just leave the catalytic converter on and don't monkey with the pipe diameter.

Indeed, while idling, most types of mufflers are the same, since there's barely any exhaust gas flowing (the fast-moving kind). However, once you start to accelerate (and hence burn more fuel in the engine), the straight-through muffler won't be able to remove as much acoustic energy from teh exhaust gas as the reverse-flow muffler will.